Spatial decomposition of predation risk using resource selection functions: an example in a wolf-elk predator-prey system

Oikos ◽  
2005 ◽  
Vol 111 (1) ◽  
pp. 101-111 ◽  
Author(s):  
M. Hebblewhite ◽  
E. H. Merrill ◽  
T. L. McDonald
2012 ◽  
Vol 279 (1747) ◽  
pp. 4626-4633 ◽  
Author(s):  
Nicholas J. DeCesare

Predation risk is an important driver of ecosystems, and local spatial variation in risk can have population-level consequences by affecting multiple components of the predation process. I use resource selection and proportional hazard time-to-event modelling to assess the spatial drivers of two key components of risk—the search rate (i.e. aggregative response) and predation efficiency rate (i.e. functional response)—imposed by wolves ( Canis lupus ) in a multi-prey system. In my study area, both components of risk increased according to topographic variation, but anthropogenic features affected only the search rate. Predicted models of the cumulative hazard, or risk of a kill, underlying wolf search paths validated well with broad-scale variation in kill rates, suggesting that spatial hazard models provide a means of scaling up from local heterogeneity in predation risk to population-level dynamics in predator–prey systems. Additionally, I estimated an integrated model of relative spatial predation risk as the product of the search and efficiency rates, combining the distinct contributions of spatial heterogeneity to each component of risk.


Author(s):  
Richard K.K. Huang ◽  
Quinn M.R. Webber ◽  
Michel P Laforge ◽  
Alec L. Robitaille ◽  
Maegwin Bonar ◽  
...  

The interplay of predator encounters and anti-predator responses is an integral part of understanding predator-prey interactions and spatial co-occurrence and avoidance can elucidate these interactions. We conducted hard-part dietary analysis of coyotes (Canis latrans Say, 1823) and space use of coyotes and caribou (Rangifer tarandus Gmelin, 1788) to test two competing hypotheses about coyote and caribou predator-prey spatial dynamics using resource selection functions. The high encounter hypothesis predicts that coyotes would maximize encounters with caribou via high spatial co-occurrence, whereas the predator stealth hypothesis predicts that through low spatial co-occurrence with caribou, coyotes act as stealth predators by avoiding habitats that caribou typically select. Our dietary analysis revealed that ~46% of sampled coyote diet is composed of caribou. We found that coyote share space with caribou in lichen-barren habitat in both summer and winter and that coyotes co-occur with caribou in forested habitat during summer, but not winter. Our findings support predictions associated with the high encounter predator hypothesis whereby coyotes and caribou have high spatial co-occurrence promoting caribou in coyote diet.


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